The Best Book Ever is the Episode of Little Bill.
Summary[]
Brenda takes Little Bill to the library so he get his first library card and check out a book. He checks out a book called, "A Day in the Life of a Hamster" and tells Miss Milkin, the librarian that it's the best book ever. All week long, he reads the book over and over. When it's time to return the book, Little Bill tells Brenda he doesn't want to, because he likes it too much. When Miss Milkin asks what he liked about it, Bill realizes he has memorized the story, and can remember it, so he returns the book and checks out another.